Don’t Make Your Trees Compete. Remove Grass & Weeds!

An open invitation to party with a string trimmer or lawnmower. Uh oh.

By Erica Timm

Trees can provide us with many, many years of amazing benefits—shade, beauty, stormwater management, increased property values, just to name a few—but first we, as their stewards, need to make sure they thrive through their first few years in the ground.

Water is the number one resource that newly planted trees need during their first few years in the ground in order to survive. While making sure you provide your newly planted trees with 10-15 gallons of water each week is a great start, removing weeds and grass growing within 18 inches of the tree trunk ensures that all of that water actually reaches the tree roots.

Plants compete with their neighbors for water, resources and rooting space. The majority of the fine, water-absorbing tree roots can be found in the top six inches of soil. This is the same space that the majority of grass and weed roots are also found. It is more difficult for the newest plant in the landscape to compete with more established plants. So it’s especially important that the grass and weeds surrounding a newly planted tree are continuously removed.Read More

It’s getting dry & warm out there …


We’re seeing some gorgeous sunny spring days recently, which means…it’s time to start watering your young tree(s)!  A newly planted tree needs at least 10-15 gallons of water each week from roughly now until late September for the first three years in the ground to ensure that they thrive going forward.  Providing one deep watering over the entire root system per week is recommended. You can think of it as giving your tree a weekly rain shower – every Saturday morning, for example.  If we have approximately 90-degree or warmer weather consistently or if your tree shows any signs of being thirsty (wilting, browning leaf margins, etc), it wouldn’t hurt to double up and water both Tuesday and Saturday that week.

There are a number of different ways to make watering easier. You can easily construct your own 5-gallon bucket drip system or purchase a 15-gallon slow-release watering bag (such as a gator bag). Please note we no longer will be offering these from the Friends of Trees as we have in years past, but that is because they are readily available online and in local hardware and garden stores.  Also, be sure to check out our Tree Care  page to get all the details on taking care of your new investment.

Remember that weeds and grass compete with your tree for water.  Please maintain the mulch for your tree(s) and hand pull weeds. When you mulch, be sure that there is a 3-6” radius from the base of the trunk of the tree that is free of mulch.  You want that space clear so there’s no moisture held at the base of the trunk, which can rot the tree’s root crown.  The moisture held by mulch should be above the growing root tips as they grow outward from the trunk, for the most part within about 18″ of the soil surface.  Also, please be careful not to damage the tree bark with lawn mowers, weed eaters, or car doors.  The bark is what contains a tree’s water and nutrient transportation system; it also keeps insects and diseases out.

We have volunteer Summer Inspectors out visiting every street and yard tree planted in the previous season, and they keep us informed on the health of the trees we plant.  If you have a tree that isn’t looking so great, please trust that after Summer Inspectors complete their routes this summer we will then determine if staff needs to check on your tree.

Portland Urban Forestry recommends an annual root pruning for trees planted in the streets, especially those in narrower planting strips, to discourage roots from growing under sidewalks. Here is a link  to learn more.

Pay it Forward!  Friends of Trees couldn’t reach our high goals without supporters like you.  In order to continue providing tree discounts and plant in as many neighborhoods possible, we need your help! Please consider making a donation to help us grow our urban forest for both this and future generations.

Hopefully we’ve answered your questions and you’ve found these links helpful, but feel free to contact us if you have any questions at 503-595-0212 or email me at .

Drip Drip,


Tree care – we do that too!

Congratulations, you helped plant 50,000 trees and native shrubs last season! Now what? Good thing Friends of Trees isn’t just a tree planting organization–tree care is also on the list because we want the trees we plant to survive and grow and thrive.

It works.The survival rate for urban trees planted the Friends of Trees way, together, with guided post-planting care from our Tree Team, is 97% (based on Portland street trees planted last season). For the subset of trees we’ve been monitoring for nine years since planting it’s an 88% survival rate.

Our trees planted in natural areas also have strong survival rates, especially given some very challenging conditions; for example, some planting sites are not accessible for watering; some plants get eaten by wildlife; humans sometimes trample or vandalize; etc. Some studies indicate that an acceptable minimum survival rate for riparian area restoration plantings is 50%, so our survival rates of 81% in year one and 70% after three years are particularly impressive.

How do we help trees thrive?

We water. We prune. We mulch. We visit and assess. We do this for the street and yard trees planted through our Neighborhood Trees program as well as for the native trees and shrubs planted in our Green Space program.

As part of our Neighborhood Trees post-planting care, we:

  • continually share information with tree-recipients about how much water, mulch and pruning trees need;
  • deliver and apply free mulch soon after trees are planted;
  • offer a summer watering service for a reasonable fee;
  • have a Summer Inspector program where trained volunteers visit all newly planted trees twice in the first summer after planting to inspect for tree health, leaving tree care info for the tree recipient.
  • have a longer term monitoring program where we visit subsets of trees planted anywhere from two to 10 years ago, to track health and growth;
  • prune trees throughout the year (except for a few weeks in the spring and fall  when trees are budding or dropping leaves). We rotate neighborhoods each year and focus most of our work on low income, low canopy and/or historically under-served communities.

Did we mention we prune? Last season we pruned more than 1,600 street trees, which is vital toward proper growth and really helps them survive wind, snow, and ice storms.

Our Green Space program also cares for the new trees and shrubs planted in natural areas, and we do this for up to 10 years after planting. The team is often joined by employee volunteer groups who help with summer maintenance tasks such as watering, mulching, and weeding (also called “day-lighting” since we’re clearing space around new plantings to provide for more light and air, and to reduce competition with weeds). We also assess for survival and replant when necessary.

Volunteers help with this! We train volunteers to inspect and prune trees, and volunteers are crucial to effectively mulching thousands of new trees at tree care events.

All told, we care for and monitor more than 54,000 trees a year!

We’re spreading the good word about trees.

We spend much of the summer spreading the word. Our Volunteer & Outreach Team, aided by dedicated Tree Team Ambassadors, attend events, festivals and fairs; plus, we have a crew of Canvassers who go door to door in priority neighborhoods. We strive to reach historically under-served, low-canopy neighborhoods with information about how to volunteer with us and how to get a tree from us. Interested in being a part of this? We’d love for you to join us.

Tree Care Guide

New Tree Care Guide

Learn how to help your new tree thrive.

Congratulations on planting a new tree!

Your young tree should provide you with many years of enjoyment and environmental benefits. Friends of Trees encourages you to read the following information carefully and to take good care of your tree to help it thrive.


Trees need to be watered regularly during their first three summers after planting to survive. Water newly planted trees with 10-15 gallons of water once a week throughout the summer and during other dry spells. A dry spell can be characterized by two to three weeks without significant rainfall in the summer or winter.

Water slowly so that moisture soaks deeply into the soil and water doesn’t run away from the root zone. Mulching is a great way to hold water in the soil for your new trees. Our videos offer quick tips on how to use slow-drip watering systems such the five-gallon drilled bucket to water your trees more effectively. Friends of Trees sells ooze tube watering bags at our office for $18 each. Please call in advance to check availability.


Mulch reduces evaporation, delivers organic nutrients, and helps prevent the growth of weeds. It is very important to mulch your new trees. Mulching prevents lawn mowers and string trimmers from getting close to the tree and damaging the trunk, which is the number two cause of tree failure. Mulching is second to watering in importance to the health of newly planted trees.

But be sure to pull the mulch away from the bark of the tree in a three-inch radius to prevent fungus growth or infection. Remember the 3-3-3 Rule: 3 inches away from the trunk of the tree, 3 inches deep, in about a 2-3 foot radius. Do not “Volcano Mulch” your tree by piling mulch up against the bark.

Removing Weeds & Grass

Keep all weeds, grass and other plants 18″ from the trunk of your new tree.

Weeds and grass in your tree’s root zone absorb water and nutrients that should be reaching the tree’s roots. They can greatly stress your new trees by creating a tougher establishment zone.

Removing weeds by hand reduces the risk of trunk damage from lawn mowers and string trimmers—a leading cause of urban tree failure.


Properly pruning your tree is critical for its health and survival; below is a quick guide to pruning your tree. Interested in a more in-depth pruning guide? Visit our pruning page here.

Pruning basics

A young tree needs all the nutrition it can get from its leaves to develop strong roots, so during the first year after planting, only broken or dead branches should be pruned.

Sucker growth, young shoots growing from the base of the tree, should be removed at ALL times.

In the second year or third year, if the tree is growing well, structural pruning can be considered and is recommended. Street trees in the cities of Portland and Vancouver require a permit through Urban Forestry to prune.

There are several important keys to properly pruning young trees. Remember, you can always hire a certified arborist, and be sure to take a minute to check out these two great resources before you start pruning: Arbor Day Foundation’s Animated Pruning Guide and Ed Gilman’s Developing a Preventative Pruning Program: Young Trees. With proper structural pruning, your tree will truly become an asset, and living legacy, to the rest of the city.

Never top your tree

Topping is the indiscriminate removal of a tree’s branches to stubs and is perhaps the most harmful tree pruning practice known; yet, topped trees are still a common sight.

Not only does topping result in tree stress, decay, hazard and sunburn; it’s also ugly and expensive. Once you top a tree, you resign yourself forever to a maintenance treadmill as your tree rapidly declines and becomes increasingly costly to care for.

Have you recently planted a fruit tree? Here are the basics of fruit tree pruning.

Powdery mildew is common on Oregon White Oaks, but it rarely causes any more than cosmetic damage.
Rust fungus is common on serviceberries in wet seasons

Insects & Disease

Friends of Trees chooses trees based on their resistance to insect and disease, but if you think your tree has a problem, resources are available to help you find a solution.

Contact your local Extension office. The Cooperative Extension Service is a collaboration between the U.S. Dept. of Agriculture, state and local governments, and land-grant universities. Every U.S. county has an Extension office to deliver research-based information on gardening, agriculture, and pest control to the general public. You can find your local Extension office using a map on the website for the National Pesticide Information Center.

Ask a nursery. Bring a leaf or twig from your tree to your local retail nursery.

Hire an ISA-certified arborist. You can find a list of arborists certified by the International Society of Arboriculture who support Friends of Trees on our arborist page.

Friends of Trees does have ISA-certified arborists on staff, but as a non-profit, our time is dedicated to planting and establishing trees and we unfortunately do not have the capacity to spend the appropriate time to properly diagnose and treat insects and diseases.

Stakes & Twine

Keep your tree staked and twined for  a year after planting to provide support during storms and to provide protection from foot traffic or car doors. After about a year, twine and stakes should be removed. Loosen any ties if they become tight around the trunk or begin to chafe away the bark. This can cut off the nutrient and water flow to the tree.

Feeling Stumped?

Feel free to give us a call at 503-595-0212 or shoot us an email at with your question or a description of your problem, along with a photo and your street address. We’ll do what we can to help!

Didn’t plant your tree with Friends of Trees? We’d love to help, but as a non-profit our capacity is limited to supporting tree planters who participate in our planting program. We recommend contacting your municipality’s urban forestry department.

From tiny seed to street giant

When our volunteers deliver a tree to your curb by pickup truck or bike trailer, the tree just sort of appears—poof!—like magic. (Our volunteers are pretty magical.) But the story of that young tree goes back 3-7 YEARS when it was a tiny seed in a greenhouse.

Where does Friends of Trees get its trees? From 10-15 nurseries located within about an hour of Portland. We only use local nurseries and don’t accept donated trees, ensuring highest quality.

“A good number of these nurseries have had relationships with Friends of Trees for years,” says Whitney Dorer, our Neighborhood Trees Manager.

One of those nurseries is Rigert Shade Trees  in Aloha. Owner Vince Rigert says our relationship started with a phone call more than a decade ago, and now Friends of Trees is his largest nursery customer.

“Now we’ve both gotten a little bigger, and I’m really happy that we’re able to do business,” Rigert says.

Gingko seedling
Depending on the species, it can take years for a tree to grow 1 or 2 feet tall. Photo: Creative Commons

From a tiny seed in a greenhouse, a tree spends its first year or two growing to be a foot or so tall. That’s when Rigert Shade Trees plants it in a pot or in the ground.

Rigert Shade Trees
Nurseries try to grow trees with strong, upright branch structure. Photo: Rigert Shade Trees

For the next several years, growing a strong branch structure is really important. “You have to keep an eye on it all growing season long,” says Rigert. Ideally a tree grows with a strong main trunk and no competing leaders, which create a “Y” shape and a weaker structure. The nursery keeps weeds away from the tree and fertilizes its roots so it grows strong.

Volunteers load trees into a big moving truck to take to the neighborhood staging area. Photo: FoT File
Volunteers load trees into a big moving truck to take them from the nursery to your neighborhood. Photo: FoT File

Finally, it’s time for the tree to make its trip to the city. All along, the nursery has been managing the roots and “root pruning” where necessary. This ensures that when the tree is dug up, the important roots come with it. “This gives the best survivability, because the roots give all the water and nutrients to the tree,” Rigert says.

Trees are delivered to the neighborhood staging area and ready to plant! Photo: FoT File
Trees are delivered to the neighborhood staging area and ready to plant! Photo: FoT File

The Friday before a neighborhood planting, staff and volunteers pick up the trees from nurseries in a big Penske truck. Sometimes they get delivered to the neighborhood staging site.

Friends of Trees Beaverton planting
Neighbors plant the tree together! Photo: FoT File

When the tree gets planted along your street, it’s about 3-7 years old with a trunk that is at least 1.5 inches in caliper (diameter). This is mature enough to survive the tough early years as a street tree while still young enough that transplanting doesn’t shock the roots. Plus, the root ball is not too heavy for volunteers to lift.

From there, the tree’s story continues for decades, as the it grows tall in your neighborhood!